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Digital object identifier

In computing, a Digital Object Identifier or DOI is a persistent identifier or handle used to uniquely identify objects, standardized by the ISO.[1] An implementation of the Handle System,[2][3] DOIs are in wide use mainly to identify academic, professional, and government information, such as journal articles, research reports and data sets, and official publications though they also have been used to identify other types of information resources, such as commercial videos.

A DOI aims to be "resolvable", usually to some form of access to the information object to which the DOI refers. This is achieved by binding the DOI to metadata about the object, such as a URL, indicating where the object can be found. Thus, by being actionable and interoperable, a DOI differs from identifiers such as ISBNs and ISRCs which aim only to uniquely identify their referents. The DOI system uses the indecs Content Model for representing metadata.

The DOI for a document remains fixed over the lifetime of the document, whereas its location and other metadata may change. Referring to an online document by its DOI provides more stable linking than simply using its URL, because if its URL changes, the publisher only needs to update the metadata for the DOI to link to the new URL.[4][5][6]

The developer and administrator of the DOI system is the International DOI Foundation (IDF), which introduced it in 2000.[7] Organizations that meet the contractual obligations of the DOI system and are willing to pay to become a member of the system can assign DOIs.[8] The DOI system is implemented through a federation of registration agencies coordinated by the IDF.[9] By late April 2011 more than 50 million DOI names had been assigned by some 4,000 organizations,[10] and by April 2013 this number had grown to 85 million DOI names assigned through 9,500 organizations.

DVD

DVD (an abbreviation of "digital versatile disc"[1][2] or "digital video disc"[3]) is a digital optical disc storage format invented and developed by Panasonic, Philips, Sony and Toshiba in 1995. The medium can store any kind of digital data and is widely used for software and other computer files as well as video programs watched using DVD players. DVDs offer higher storage capacity than compact discs while having the same dimensions.